What is the purpose of a collar beam in roof construction?

The primary purpose of a collar beam in roof construction is to tie opposite rafters together. This connection helps to stabilize the rafters and maintain the structural integrity of the roof system. By tying the rafters at a specific height, the collar beam helps to prevent them from spreading apart, which can occur due to the weight of the roof materials or snow load. This feature is particularly important in roofs with a steep pitch, where the rafters can exert outward forces on the walls.

The collar beam also plays a role in distributing the load across the rafters and can help maintain the shape of the roof over time, reducing the risk of sagging or structural failure. Properly installed collar beams contribute to the overall strength and durability of the roof structure, making them an essential component in various roofing designs.